Method of obtaining metallic compounds from silicates



Ami? 29, 1924 1,492,016

c. M C. BROWN METHOD OF OBTAINING METALLIC COMPOUNDS FROM SILICATES Filed April 5 1922 CHARLES McGOMBIE BROWN, OF TORONTO, ONTARIO, CANADA.

METHOD OF OBTAINING METALLIC COMPOUNDS FROM SILICATES.

Applicatlon flled April 8, 1822. Serial No. 549,238.

county of York, Province of Ontario, in the Dominion of Canada, have invented certain new, and useful Improvements in Methods of Obtaining Metallic Compounds from silicates, described in the following specification and illustrated in the accompanying drawings, that form part of the same.

The principal objects of the invention are to enable the recovery of the maximum quantities of oxides at the minimum expense and to enable the continuous operation of the plant and further, to. enable operation at a low temperature.

The principal feature consists in treating the silicates in a dry state with a sulphurous gas in the presence of a catalyzer to resolve the oxides to sulphates.

In the accompanying drawings Figure 1 is an elevational view intermediately broken and shown in part section of an apparatus for carrying this method into efiect.

Figure 2 is a vertical mid-sectional view taken on the line 2-2 of Figure 1 and showing a hood over the rotary kiln.

Figure 3 is a plan view of the feeding end of the apparatus with the hoppers removed.

To describe the apparatus, a rotary kiln 1 is supported at a suitable incline on the roller bearing standards 2 and is rotated by a chain belt 3 driven by a suitable motor 4.

Underneath the kiln are arranged suitable gas burners 5 which may be accurately regulated to maintain a uniform temperature throughout the length of the kiln,jthe desirable temperature being approximately 800 de ees Fahrenheit.

The iln 1 is provided with longitudinally arranged ribs 6 extending inwardly. These ribs are adapted to lift the powdered silicate and then 'spill it through the gases contained in the ,kiln. These ribs may be arranged spirally if desired to maintain a continuous spilling of the powdered silicate.

At the reed end of the kiln is arranged a cap 7 which is connected thereto in a gas tight joint.

A frame 8 is arranged at the feed end and on this frame is supported a hopper 9 which is connected by a pipe 10 to t e cap 7 and is rovided with suitable means for feedin t e finely pulverized silicate into the ki a A hopper 11 is supported on the frame and is adapted to contain an alkali fluoride or fluoride of alkaline earth and below the hopper is arranged a heater receptacle 12 adapted to contain a quantity of sulphuric acid. The fluoride is fed into a p1 e 13 which enters the receptacle 12 and a arger pipe 14 surrounding the lower end of the pipe 13 forms a conductor for the hydrouoric acid gas generated.

A fan 15 is connected with the pipe 14 and forces the hydrofluoric acid gas to a conduit 16 which enters the cap 7.

Sulphurtrioxide is introduced into the kiln, being repared in any suitable manner. The S0 is ere shown as produed by feeding iron pyrites to a heater 18 through a hopper 17 and pipe 19. The gas rises in the larger pipe 20 surrounding the pipe 19, being drawn upwardly by a fan 21 which discharges into the conduit 16 and mixes with the hydrofluoric acid gas fed from the heater 12. 7 Air is fed to the heater 18 by a small pipe 22 leading from the fan 21 'to the pipe 19.

From this description it will be seen that the sulphur trioxide (S0,) is thoroughly mixed with the hydrofluoric acid gas (HF) and these flow through the kiln, while the powdered silicate is continuously spilled through the gas and the catalytic action of these gases converts the metallic oxides in the silicate to sulphates.

It is important to note that the flow of the gases through the kiln is comparatively slow, as the heating of the kiln is effected externally and is not dependent upon a draft through the kiln to maintain combustion.

In treating the silicates in the manner described. the silicates which are in a perfectly dry state are not attacked by the hydrofiuoric acid gas but such gas acts as a catalyzer between the metallic oxides in the silica and the sulphur trioxide and forms them into sulphates.

The reaction taking place if feldspar is used is illustrated by which product is aluminum sulphate, potas-.

hydrofluoric acid gas, which acts'as a catalyzer and does not actually enter into the reaction, is carried oil through the pipe 24, from whence it is brought into contact with an alkaline hydrate to form a fluoride and it is then returned to-the hopper to be used again.

A process and apparatus such as described may be operated continuously and the results obtained are the recovery of the metallic oxides at extremely low cost and in continuous quantity.

What I claim as my invention is 1. A method of extracting metallic oxides from silicates, consisting in subjecting the pulverized silicate in a dry heated state to theaction of a sulphurous gas in the presence of a gaseous fluorine compound.

2. A method of extracting metallic oxidesfrom silicates, consisting in subjecting the pulverized silicate in a dry heated state to the action of sulphur trioxide and hydrofluoric acid gas.

3. A method of extracting metallic oxides. from silicates, consisting in passing the dry pulverized silicate through a rotary kiln externally heated and subjecting it to the action of a sulphurous gas in the presence of a gaseous fluorine compound catalyzer.

4. A method of extracting metallic oxides from silicates, consisting in introducing the pulverized silicate into a rotary kiln externally heated and blowing a mixture of sulphur trioxide and'hydrofluoric acid gas through the kiln, and recovering the hydrofluoric acid gas from the discharge end of the kiln. v

5. 'A method of extracting metallic oxides from silicates, consisting in introducing the pulverized silicate into a rotary kiln externally heated, producing sulphur trioxide in a .suitable apparatus, producing hydrofluoric acid gas in a suitable apparatus, then mixing the gases produced and passing them through the kiln.

CHARLES MoCOMBIE BROWN. 

